The present invention relates to a rivet feeding apparatus for riveting guns.
The present apparatus is used specifically for automatically and continuously arming tear-off rivets pre-mounted on the tear-off nail.
Particular reference is made to a device of the type comprising: a conveyor for rivets fitted with nail and collar, on which the rivets advance one after the other hanging by the collar with the nail facing downward; a device for upsetting the rivets exiting the conveyor, means for transporting the rivets from the upsetting device to a front arming device; and a front arming device provided to load the rivets onto a riveting gun.
In devices of this kind the aforesaid conveyor comprises a pneumatic feed tube in which the rivets advance with the nail facing backward with respect to the direction of travel; the upsetting device receives a rivet which exits the conveyor with the nail facing downward and arranges it with the nail facing upward and facing an inlet of the pneumatic feed tube; the rivet is pushed into the tube by the action of the compressed air and is hurled towards the arming device.
This known apparatus presents some drawbacks; at the origin of such drawbacks is the fact that the compressed air used to transport the rivets along the aforesaid feed tube presents quite a high pressure, usually equal to 6 bar, which is the same as that utilized in other "power" sections of the riveting guns, used for arriving and setting the rivet in place. Because of the use, in the aforesaid feed tube, of such a high pressure the rivet attains a very high speed and a large amount of kinetic energy, and it may occur that, having violently stricken a portion of the arming pincer, the rivet nail could depart the related seat in an uncontrolled manner.
This could be dangerous for personnel tasked with using the rivet gun.
Moreover, compressed air consumption is quite high and the pneumatic ducts within which the rivets transit to reach their arming section are subjected to intense wear.